KR19990086076A - Automatic vibration measuring device displacement measurement device using serial communication and its method - Google Patents

Abstract

The present invention relates to a system for automatically measuring a plurality of vibrating wire type measurement sensors using serial communication, in particular, the length of various structures due to the influence of the ground behavior, vibration, etc. in civil engineering-related construction sites, such as roads, bridges Applied to the measurement and management of deformation, underground earth pressure and gap hydraulic displacement.

The system configuration for automatically measuring the plurality of measurement sensors includes a detection sensor unit for detecting the vibration of the piano wire embedded in a plurality of vibration measurement sensors for civil engineering measurement, a vibration generating unit for driving the detection sensor unit to vibrate the piano wire; A frequency input section for accepting the vibration frequency, a square wave converter section for converting the frequency into a square wave, a microprocessor section for counting square pulses, converting the digital data into digital data, and transmitting and receiving the data, and a serial communication method It is characterized by consisting of a serial transmission and reception unit for transmitting the data, a sensor control unit for receiving and storing this data serially and control, and a main computer for receiving and analyzing measurement data by the sensor control unit.

Therefore, it is possible to easily and easily measure various vibration sensors such as length strain gauges, pore pressure gauges, earth pressure gauges, etc. at the civil engineering site, and digital conversion is performed directly at various displacement sensors, so that they can be transmitted without loss due to long lines. Civil engineering measurement with high precision can be realized.

Description

Automatic vibration sensor displacement measurement device using serial communication and its method

The present invention relates to a system for automatically measuring a plurality of vibrating wire type measurement sensors using serial communication, in particular, the length of various structures due to the influence of the ground behavior, vibration, etc. in civil engineering-related construction sites, such as roads, bridges Applied to the measurement and management of deformation, underground earth pressure and gap hydraulic displacement.

In the civil engineering field, a vibration string type sensor is used to measure the displacement amount of a structure and the ground, that is, a sensor that measures the displacement amount by changing the frequency of the piano wire when both ends of the piano wire are fixed to a fixed point and one fixed point is moved. . This moving fixed point of the vibrating wire sensor, that is, the moving end is changed by changing the length, the pressure of the water, etc. The change is a length extensometer according to the length change, a pore pressure gauge according to the pressure change of the water, According to the change in the pressure of the soil, it is called a pressure cell, and the external shape is slightly different, but the principle of operation is the same.

However, this type of sensor has to extend the measuring line from the number of sensor installation points to the measuring point one by one, so there are too many measuring lines depending on the number of sensors. have.

Referring to FIG. 1, a typical civil engineering measurement example of measuring various displacements in a civil engineering site using the vibration string type sensor as described above will be described. Examples of this include rod extensometers, piezometers, and pressure cells.

First, as a vibration string length strainer 10, in order to measure the change of settlement, etc. according to the depth of the underground soil, the measurement rod as much as the underground measurement depth is lowered to the ground and the end is fixed to the bottom of the ground (Groutable Anchor). And measure the length displacement of the rod by connecting the measuring line 13 to the manual measuring device 14 in the vibrating wire sensor at the top.

Next is a vibrating wire gap pressure gauge (11), in order to measure the pressure of the water in a certain depth of the underground buried a pipe (pipe), the vibration wave pressure gap pressure sensor (11) in the tube and pull the measuring line 13 The water pressure is measured with a manual measuring instrument 14.

Finally, as a vibration expression tonometer 12, in order to measure the pressure of the soil of a certain depth in the ground buried a tonometer sensor 12 at a constant depth and pull up the measurement line to measure the earth pressure with a manual measuring machine (14).

In addition to the civil vibrating string measuring instrument measured in the above manner there are a large number such as a pressure gauge (Loadcell), strain gauge (Strain Gauge). Therefore, when various types of vibration expression sensors are not installed at one point but multiple points are installed in multiple layers by depth, the measurement lines are numerous.

Fig. 1B is a schematic diagram of a line configuration of such a conventional measuring method. In this conventional method, the sensor increases by two lines for every one sensor, and the measuring method and measurement system are inefficient, and the noise due to the long line is large, resulting in a large error due to signal attenuation.

The conventional measuring device, which is a little more improved than the above, may be a device in which the measuring line 13 is connected to the manual measuring instrument 14 and the line selection switch is automatically selected (Mutiplexing). Since there are many measuring lines and the signal lines 13 of each sensor are gathered in one place as shown in FIG. 1B and concentrated on the measuring device 14, the lines are very complicated and the wiring work is difficult.

In such a prior art, there are many limitations and limitations in measuring civil displacement with vibration sensor in the rapidly developing civil measurement field.

As described above, in the field of civil engineering measurement in the prior art, in view of various working conditions, automatic measurement and high precision measurement are urgently required, but still rely on the conventional low-precision manual measurement of the conventional method.

The technical problem to solve this problem is to reduce the control measurement line and to digitize the output signal of the sensor in the sensor itself in order to configure a system suitable for the measurement work conditions for civil engineering automation and its measurement data It is a technology to communicate data to the main computer in a compact and compressed signal method.

The present invention has been made in view of the above-described problems of the prior art, the purpose of which is the electrical signal to the various displacements in the ground and various displacements of the civil structure that may occur when excavating the underground for civil engineering-related construction The present invention provides an automatic displacement measuring device for various displacements at a civil engineering site that can be converted and automatically measured remotely by a serial communication method.

In order to implement the serial communication method, a signal conversion unit is attached to various vibration expression displacement sensors, and the conversion unit has a function of converting a measurement signal into digital data and serial transmission and reception by driving the vibration string sensor.

Another object of the present invention is to permanently measure the changes in civil engineering structures and grounds caused by the natural environment or poor construction of the outside, not permanently, and the measurement sensor is permanently installed at the measuring point of the measurement site, and the data communication line It is to provide an automatic measuring method that can measure the displacement of the structure automatically in the office by using the office, and can measure the displacement of the civil engineering permanently until the life of the structure is permanent, regardless of the measurement time and place.

Figure 1a is a schematic cross-sectional view showing a conventional passive vibration string sensor displacement measuring device,

Figure 1b is a line configuration diagram connecting the conventional vibrating wire sensor,

Figure 2a is a schematic cross-sectional view showing a vibrating string sensor automatic measuring device according to the present invention,

2b is a block diagram connecting the vibration string sensor according to the present invention,

3 is a vibrating wire type sensor configuration diagram

4 is a detailed block diagram of a vibrating string sensor automatic measuring device according to the present invention;

5 is a flowchart of a signal conversion unit shown in FIG. 4;

FIG. 6 is a flowchart of a sensor control unit shown in FIG. 4;

7A is a serial communication protocol for transmitting to a sensor signal converter;

7b is a serial communication protocol received from a sensor controller,

FIG. 8 is a circuit diagram of the signal converter shown in FIG. 4.

(Explanation of symbols for the main parts of the drawing)

10; Length strain gauge of vibration string sensor method 11; Pore pressure gauge with vibration string sensor

12; Earth pressure gauge with vibration string sensor 13; Manual measuring cable

14; Manual measuring machine 20; Signal converter

21; Serial communication line 22; Sensor control unit

23; RS-232 connection cable 24; Main computer

30; Mobile stage 31; Piano line

32; Fixed end 33; Sensor detector

34; Vibration string driving unit 40; Vibration String Measurement Sensor

41; Frequency input section 42; Square wave transformation

43; Measuring microprocessors 44,46; RS-485 converter

45; Vibration generator 47; Control microprocessor

48; Serial TX / RX Driver 49; LCD panel

50; Data storage memory 51; Nonvolatile Memory (EEPROM)

80; Amplifying transistors 81,82; Operational amplifier

83; Three-contact relay 84; Switching transistor

85; Electrolytic Capacitors

In order to achieve the above object, the present invention provides a plurality of vibration expression sensors installed at a plurality of points to be measured and the vibration frequency is changed according to the physical displacement amount of each point, and a plurality of vibration expression sensors together with the plurality of vibration expression sensors It is installed at the measuring point and converts the signal from each sensor to digital, the signal conversion means for transmitting a plurality of conversion data by serial communication method, and periodically send a control signal to the plurality of signal conversion means sequentially Automatic sensor vibration displacement characterized in that it comprises a sensor control means for controlling the transmission and storage of the converted measurement data in the serial, and the main computer to receive and analyze the measurement data received from the sensor control means and informs Provide a measuring device.

In addition, the sensor control unit and each of the inclination sensor signal converter is connected to a serial communication line by the multi-point mode (Multi_Point Mode) method, characterized in that to collect the data in a way that a plurality of sensors are connected to one line.

The physical displacement represents the length displacement of the civil engineering structure, the pressure of soil in the ground, the pressure of water in the ground, and the amount of soil in the ground sinking underground.

In addition, according to another feature of the present invention, a plurality of vibration sensors installed in a plurality of points to be measured for sensing the physical displacement amount of each point, a plurality of signals having a data transmission and reception function connected to each of the vibration expression sensors In the vibration sensor automatic displacement measurement method consisting of a conversion unit, a sensor control unit installed at a remote site, a main computer for analyzing the measurement data, the vibration expression sensor to each of the plurality of signal converters sequentially by the sensor control unit by the serial communication protocol method Instructing the measurement data conversion operation of the signal; and each signal conversion unit waiting for monitoring the serial communication line at all times recognizes its own address, converts the detected physical displacement into measurement data, and converts the converted digital data into serial data. Transmitting to a sensor controller by a communication method, Storing the collected data by the real communication method, displaying information such as measurement time and stored data on the indicator, and then transmitting the collected data to the main computer, analyzing and charting and informatizing the data received from the main computer. It provides a vibration expression sensor displacement automatic measurement method characterized in that consisting of a step.

According to the present invention, the main computer is located in the office and can perform automatic measurement unattended, and the modem can be connected to the remote central computer communication network, so that the measurement data processing is more rapid regardless of time and place. And convenient.

(Example)

Hereinafter, with reference to the accompanying drawings showing a preferred embodiment of the present invention described above in more detail.

2a is a schematic cross-sectional view showing an automatic vibrating string sensor according to the present invention, Figure 2b is a schematic diagram of a line connecting the vibrating string sensor according to the present invention, Figure 3 is a vibrating string type sensor configuration, Figure 4 according to the present invention 5 is a detailed block diagram of an apparatus for automatically measuring a vibration string sensor, FIG. 5 is a flowchart of a signal converter shown in FIG. 4, FIG. 6 is a flowchart of a sensor controller shown in FIG. 4, and FIG. 7 is a flowchart of a sensor signal converter and a sensor controller. Serial communication protocol.

First, with reference to Figure 3 with respect to the Vibrating Wire (Vibrating Wire Type Sensors) briefly described as follows.

Vibration expression sensor is a very simple sensor that is commonly used in civil engineering, and it shows the change of vibration frequency of piano wire according to the length of piano wire as sensor displacement. In the structural description, both ends of the piano wire 31 are fixed to the fixed end 32 and the moving end 30, and a sensor detecting unit 33 in which a coil is wound around a permanent magnet on an upper end of about 1 mm in the center of the piano wire. ) Is located.

The moving end 30 is moved from side to side by the driving unit 34 that changes according to the applied sensor method, that is, the length or the amount of pressure displacement, so that the frequency of the piano wire is changed, and the sensing unit 33 measures the detected vibration current amount. Through (13), it is a structure that reads the displacement amount by a general measuring device which is separated by a certain distance.

Therefore, the present invention simply replaces the signal conversion unit 20 of FIG. 4 with the vibration string type displacement meter 40 so that the frequency of the piano wire can be read as a measured value without a distance at the rear end of the sensor detector 33 made of a permanent magnet and a coil. Immediately attached to the rear end without a distance, it is composed of a digital serial communication line 21 as shown in Fig. 2b to transmit and receive measurement data.

The operation flow of each part of the present invention will be described in more detail with reference to FIG. 4, and the frequency input part 41 converts the vibration current induced in the coil of the sensor detector 33 into a frequency. This vibration current is generated by vibrating the piano wire by virtue of generating a voltage of DC 12-24V instantaneously in the vibration generating unit 45 and pulling the piano wire 31 and releasing it.

The generated frequency is about 800-2500 Hz, and the square wave transforming section 42 converts the square wave into a square wave so that the measurement microprocessor 43 can recognize it as a digital value. The measurement microprocessor 43 digitalizes the displacement and performs data communication with the sensor controller 22 through the RS-485 converter 44.

The operation description will be described in more detail with reference to the circuit diagram of FIG. 8 as follows. In order to vibrate the piano wire of the vibrating string sensor, a DC voltage is applied to the sensor detecting unit 33 to pull the piano wire and release it (Plucked). The voltage is supplied by the direct current voltage of the electrolytic capacitor, in which the direct current voltage charged in the electrolytic capacitor 85 of the capacitance 1000 microfarads (Micro_Farad) of the vibration generator 45 is connected by the three-stage relay 83. The voltage increases to 12 Volts when using two electrolytic capacitors and to 24 Volts when three are used. In Fig. 8, two are driven to 12 Volts. The voltage width is determined by the switching transistor 84 by the signal width (about 25 mSec) output from the output port PB0 of the microprocessor 43.

The vibration frequency generated by this is sensed by the sensor detector 33 and transmitted to the frequency input unit 41 and amplified by a low noise high gain transistor 80 having an amplification degree of 400 or more, about 1 It is amplified by the oscillation width of the Volt voltage and transmitted to the input terminal of the low power dual operational amplifiers 81 of the square wave transformation unit 42.

The square wave transformation unit 42 converts a square wave by two operational amplifiers 81 and 82 based on a reference voltage of a positive input terminal of an operational amplifier to convert a square wave into a square wave. It is inputted to the input port PA0 and counted.

The microprocessor (Microchip, Pic16c71) 43 converts the input sensor measurement value into a digital data value, stores it in an internal memory together with an information amount such as measurement time, and an RS485 converter (LTC485) to which a serial communication line 21 is connected. After waiting for transmission / reception using 44), if a call of its own address is detected, data communication is started.

Serial communication method which is a representative feature of the present invention will be described below with reference to FIG. 2B. Unlike the conventional method (FIG. 1B), this system can be easily constituted by two lines 21 coming out of the sensor control unit 22. As shown in FIG. These two lines adopt RS-485 communication method and the communication distance is several kilometer.

RS-485 communication supports multi-point mode. Multi-point refers to a standard that allows multiple devices to be connected to one line, each device has its own address, and then the host can send and receive devices. .

Although two lines are used as the communication method, transmission and reception may be separated and four transmission lines may be increased by a full duplex method to increase the transmission speed. It can also communicate at a low speed by using a 1 Line Bus method that transmits and receives through Half Duplex.

In order to apply the two-wire method, the piano wire 31 inside the vibrating wire displacement gauge 40, such as a pore water pressure gauge, is plunged to obtain a vibration frequency, and the frequency is converted into a digital displacement and converted into serial communication. The sensor signal converter 20 capable of transmitting and receiving data is required.

The serial communication configuration method by the signal conversion unit 20 is configured as shown in FIG. 2B to realize a high-precision civil engineering measurement that could not be realized by the conventional method in which many lines 13 are required and the measurement line is long and noise increases. There is a number.

The sensor controller 22 of FIG. 4 controls each sensor signal converter 20 to comprehensively receive measurement result data through the RS-485 converter 46, and displays the reception state on the display screen 49. The memory 50 stores displacement values of the received sensors, and the nonvolatile memory 51 stores constant data such as a sensor address and a communication standard. All these processes are controlled by a controlling microprocessor 47.

In addition, information is exchanged with the main computer 24 through a serial transmission / reception driver 48 through RS-232.

FIG. 5 shows a flowchart of a program of the measurement microprocessor 43 in the sensor signal converter 20 and the control microprocessor 47 in the sensor controller 22.

5 is a flowchart of a measurement macro processor for a signal conversion unit, which will be described in detail below.

When the power is supplied and the operation starts, the RS-485 communication port is in the standby state for input, confirming whether the vibration string sensor call signal is required for the data transmission request from the sensor control unit, or repeatedly maintaining the standby state (step S51). ). If there is a call signal, it is checked whether it is my sensor address (step S52). If the vibration string sensor displacement amount request of the My Address is performed, data conversion is performed (step S53). The converted data is stored in the memory (step S54), the data is transmitted by RS-485 communication (step S55), and the operation is terminated after confirming the data reception completion signal of the control unit. In order to save transmission and reception time, the confirmation operation may be omitted.

6 is a flowchart of a macro processor for controlling a sensor controller, which will be described below in detail.

When power is supplied to the sensor control unit and operation starts, the controller call signal from the sensor signal converting unit is waited while the RS-485 communication port is in the input state (step S61). If there is a control unit call signal, the transmission sensor address checking operation is performed (step S62). After the verification operation, the reception data and measurement time are stored in the memory (step S63), the reception completion data is sent out (step S64), the reception status is displayed on the display screen LCD (step S65), and the measurement of all installed sensors is performed. Upon completion, the data transfer operation is performed to the main computer (step S66).

7 shows a serial communication standard (protocol) between the sensor signal converter 20 and the sensor controller 22. This is described as follows.

FIG. 7A is a protocol for calling a signal converter of a sensor measured by a sensor controller, the first 16 bits of which transmits two characters (ASCII) in ASCII code as a signal for calling a vibration string sensor, and then receives a received sensor address. Send the number 8 bits. The following 8 bits are the inverted signals inverting the sensor address, that is, 1 is 0 and 0 is 1, which is a signal for preventing transmission / reception errors and may be omitted to save transmission / reception time.

7B is a protocol for transmitting the measurement result data from the sensor signal conversion unit to the sensor control unit, the first 16 bits of which transmits two characters (ASCII) in ASCII code as a signal to call the sensor control unit, and then transmits the sensor address. The number 8 bits and the inverted 8 bits are sent in succession. The next data is the 5 digits of the measurement result, which is 40 bits of data, followed by an invert signal. Again, the inverted signal can be omitted to save transmission and reception time.

For example, if the transmission / reception signal is expressed in ASCII code, it can be expressed as follows. That is, the sensor transmission code of FIG. 7A may be represented by “SN 01 FE”, and the measurement result receiving code of FIG. 7B may be represented by “MH 01 FE 31 32 33 34 35 CE CD CC CB CA”.

As described above, in the present invention, in the measurement of various displacements of structures and underground soils at civil engineering sites, it becomes possible to completely operate informational construction and civil measurement without manual conventional civil measurement.

Briefly, the effect of the invention is described as follows.

As a first effect, control lines from multiple vibrating string sensors are reduced to only 2 lines from the conventional method, which requires at least dozens of lines, so that precise measurement can be performed automatically using many sensors even in the field where there is no installation space.

Second, since the measured displacement amount of vibration frequency is converted to digital at the stage immediately after the vibration string sensor and output to the outside, it is possible to measure more precisely and losslessly than the conventional method of dragging a line more than 30 meters and converting the signal. .

Third, since the signal conversion control circuit is built-in, many expensive cables and protective tubes necessary for manual measurement are unnecessary, so that it can be manufactured at low cost and the cost is very simple to install.

Fourth, it is possible to install it as a measuring facility fixed in one place, not the conventional method of carrying a manual measuring device at the time of measurement and moving it to the point where the vibration string sensor is installed. It is possible.

Fifth, by being fixed at the measurement point, the measurement error caused by the measurement person can be reduced by measuring and displacing once, and then moving again at the next measurement time, as in the conventional measurement method.

In addition, as a last effect, the measurement time is shortened automatically because it is measured at a long distance, and labor costs are saved because there is no need for separate measurement personnel. Innovative contributions to civil engineering structures and geotechnical investigations.

While the present invention has been illustrated and described with reference to certain preferred embodiments, the invention is not limited to the above embodiments and is commonly understood in the art to which the invention pertains without departing from the spirit of the invention. Various changes and modifications may be made by those who have.

Claims (5)

A plurality of vibration expression sensors installed at a plurality of measured points, the vibration frequency of which changes according to the physical displacement of each point; A signal conversion means installed at a plurality of measurement points together with the plurality of vibration expression sensors, converting signals from each sensor into digital, and transmitting a plurality of conversion data by serial communication; Sensor control means for controlling the transmission and storage of the converted measurement data serially by periodically sending control signals to the plurality of signal conversion means sequentially; Vibration-type sensor displacement automatic measurement device characterized in that it comprises a main computer for receiving and analyzing the measurement data received from the sensor control means and information. The apparatus of claim 1, wherein the sensor control unit and each inclination sensor signal converter are connected to a serial communication line to collect data in a multi-point mode. The apparatus of claim 1, wherein the physical displacement amount is at least one of length, pressure, hydraulic pressure, and ground subsidence. Piano wires whose vibration frequency changes with length and pressure displacement, Detection sensor unit for detecting the vibration of the piano wire, A vibration generator for driving the detection sensor to vibrate a piano wire to generate a frequency; A frequency input unit for receiving and amplifying the vibration frequency; A square wave converter converting an output frequency of the frequency input unit into a square wave pulse; Control means for counting square wave pulses, converting them into digital data, and controlling data transmission and reception; A vibration expression sensor displacement signal conversion circuit having a data transmission / reception function, characterized by comprising a serial converter for transmitting the converted data by serial communication. A plurality of vibration expression sensors installed at a plurality of points to be measured to detect physical displacements at each point, a plurality of signal converters connected to each vibration expression sensor having a data transmission / reception function, a sensor control unit installed at a remote location, In the vibration sensor automatic measurement method composed of the main computer for the measurement data analysis, Instructing, by the sensor controller, a measurement data conversion operation of the vibration expression sensor to each of a plurality of signal converters sequentially by a serial communication protocol method; Each signal conversion unit waiting for monitoring the serial communication line at all times recognizes its own address, converts the detected physical displacement into measurement data, and transmits the converted digital data to the sensor control unit by serial communication; Storing the collected data by serial communication method, displaying information such as measurement time and stored data on the display, and then transmitting the collected data to the main computer; Vibration-type sensor displacement measurement automatic method comprising the steps of analyzing the data received from the main computer to plot and information.